Modeling plastic deformation and the dynamics and the statistics of the associated crackling noise in Bulk Metallic Glasses
Karin Dahmen (University of Illinois), James Antonaglia (University of Illinois at Urbana Champaign), M Wraith (UIUC), Michael Leblanc (UIUC), Wendelin Wright (Bucknell University), Todd Hufnagel (Johns Hopkins University), Peter Liaw (), Junwei Qiao (), J Uhl ()
Slip Avalanches in Amorphous Metals
Mon 9:00 - 10:30
Barus-Holley 168
Many bulk metallic glasses crackle under slow deformation Under slow compression they deform intermittently with sudden slips detected as acoustic emission and serrations in the stress-strain curves. In these materials, power laws often govern the statistics of the crackling noise. A simple micromechanical model for the deformation of solids with only one tuning parameter (weakening ) is used to interpret and understand the experimental data. The model predicts both the statistics and the dynamics of the crackling noise. It assumes that the crackling noise reflects slip-avalanches of elastically coupled weak spots in the material. It predicts stress-strain curves, acoustic emissions, related power spectra, and power-law statistics of slip avalanches, including the dependence of the cutoff on experimental parameters, such as strain rate. It also predicts the average time profiles of the slip velocity during individual slip-avalanches. These profiles reflect the details of the slip dynamics during the propagation of individual serrations or crackles. The model also predicts a continuous phase transition from ductile to brittle behavior. Material-independent (“universal”) predictions for the power-law exponents and scaling functions for both the statics and the dynamics of the crackling noise are extracted using the mean-field theory and tools from the theory of phase transitions. The results are compared with recent experimental observations on slowly-deformed bulk metallic glasses.